Installing Blender 2.78.1 - Cycles Disney Brdf
Tech Stuff first
As most Blender Branches, they are cross-platform and can be compiled for any supported operating system. Since support for compiling Blender is out of scope of BSE, I won't go into detail on how to do it. However, the documentation gives a very good starting point: https://wiki.blender.org/index.php/Dev:Doc/Building_Blender
Note that for adding the Disney Shader, you'll need to checkout a branch with GIT that actually contains the code. One such branch is the Experimental one.
Easy solution for quick evaluation on Windows
Some people actually go for the extra effort and provide self made Blender Builds on a dedicated website called GraphicAll. You can search for keywords there, Disney will give you this page as a result: http://graphicall.org/1192
Just download and unzip it to your hard drive (this is a Windows Build), and run blender.exe from that folder directly. You'll find the Disney Shader in the Add section of the node editor, together with the Diffuse, Glossy, Anisotropic,...